Gas-Phase Thiophene Hydrogenation to Tetrahydrothiophene over Sulfide Catalysts

Thiophene hydrogenation to tetrahydrothiophene over supported transition metal sulfides is studied. Comparison of the atomic catalytic activity at T = 240°C and P = 2 MPa showed that aluminosilicate-supported PdS is one to two orders of magnitude more active than Rh, Ru, Mo, W, Re, Co, and Ni sulfides on various supports. These metal sulfides are arranged in the following series according to the rate of tetrahydrothiophene formation: Pd Mo > Rh Ru > Re > W > Co > Ni. The reaction over sulfide catalysts is assumed to occur through thiophene activation on proton centers and coordinatively unsaturated cations of metal sulfides and additionally on the proton centers of support in the case of palladium catalysts.